welcome redditors!to snoo-finity ... and beyond!

NBME 24 Answers

nbme24/Block 2/Question#37

In a culture of motile spore-forming bacteria, ...

Irradiation with x-rays

Login to comment/vote.

 +6  upvote downvote
submitted by famylife(37),

"double-strand breaks...are caused by ionizing radiation, including gamma rays and X-rays." vs. "UV radiation causes two classes of DNA lesions: cyclobutane pyrimidine dimers (CPDs, Figure 1) and 6-4 photoproducts (6-4 PPs, Figure 2)."


Simply put: more energy in a light wave the more likely it is to cause cellular (DNA) damage.

Ultraviolet has less energy than X-rays (it goes through your flesh to see bones!)

Order of light strength (cell damaging capability)

  • X-Ray > UVA (also able to cause double strand break) > UVB (most likely single strand break - repaired)